Is my problem a missfire?

[2Thumbs]

Well, the ROFLver's been having problems for the last week. To a point where it's now pretty much undriveable.The problem is intermittent. It could run fine for 2 minutes, and then it'll struggle to get up a hill in 1st gear! When it's not running right, you can put your foot done and all you get is a lot of noise sounding like a low down burble (like having a cherry bomb exhaust or K&N induction kitz ).It idles fine, but it wont rev above 3k when stationary. It also starts on the button but will occasionally conk out right after.It had new plugs a month or so ago, so if it is a missfire I'm hoping it's either HT leads or coil. Maybe one of the 'new' sparks is dead even?Any suggestions?

[M'coli]

Could be fuel starvation. What car is it?

[2Thumbs]

'93 Rover 420GSi.

[Albert Ross]

Try the distributor cap......if it still has one (Not sure if they had coil packs at this age) as it might be contaminated or porous, even having corrosion on the terminals. Might be 6 or 7mm headed set screws into the head.

[2Thumbs]

Forgot to mention, it had a new dizzy cap and rotar arm not long before having new plugs.They're probably worth checking though. It's hard to tell if it's just missing on one cyclinder or more though. I'm thinking it varies as sometimes it's there but is still usable, but earlier it was like pulling a lorry with a Mini 850.

[r.welfare]

Have you changed the fuel filter recently - could the pipes be kinked?If it was a "duff" plug it would vibrate like crazy at idle - when I changed the plugs in my wife's car one had a completely closed-up gap (I know, should have checked!) and it didn't half buck around.

[2Thumbs]

That's probably the plugs ticked off the list then. I'll check fuel lines (aswell as other stuff) if it ever stops bloody raining. Good thing I have a couple days off this week.

[Futuramic]

I had exactly the same issue with the Pinto of POWAHHH in the G26. It got to the point where the car couldn't even move off in first gear and refused to rev above about 5,000.I replaced the coil, dizzy cap, rotor arm, plugs, leads, points and condensor all at the same time and the engine has run fine ever since.

[Station]

A quick way of checking fuel is spray Carb Cleaner or Easi-start into the inlet. What out for it backfiring and causing a little fire.Sounds like something's old and had it.

[daverapid]

Broken/blocked cataytic converter.

[2Thumbs]

The cat has been rattling for a couple months. But I didn't think that would cause an intermittent misfire. It's gotta be replaced in a month or so for MOT anyway.

[simmo]

The cat has been rattling for a couple months. But I didn't think that would cause an intermittent misfire. It's gotta be replaced in a month or so for MOT anyway.

The Rover Cats normally rattle because heat-shield around them rots by the bolts that sandwichs it around the cat, the shield then rattles against the cat body. I have ripped off the heatshield on one before with no adverse affects but watch put for smoking carpets . I would think an attempted lash up before buying a new Cat would be in order.With the misfire the k series leads do track across between each other , have a look when its darkish and youwill probably see it. Also the leads goes brown where its tracking so do the plug caps.

[Station]

Could be loads of things really. My mate had a transit van that had either the cat or a silencer disintegrate and was blocking the exhaust.

[daverapid]

The cat has been rattling for a couple months. But I didn't think that would cause an intermittent misfire. It's gotta be replaced in a month or so for MOT anyway.

It will cause intermittent power loss and bad running if a part of the broken catalyst is blocking the exit. Seen it many, many times.

[Guest]

Forgot to mention, it had a new dizzy cap and rotar arm not long before having new plugs.

Is the distributor of the type with an amplifier module screwed onto the side? Could be that at fault.

[2Thumbs]

All fixed! It's gone from unusable to back to how it should be with an outlay of £15 and 10 minutes of my (highly valuable ) time.It seems that decent spark plugs and a new dizzy cap/rotar arm amplified the ageing of the HT leads which, if the service history is anything to go by, were last replaced in 2005. :roll:Now I just need a new CAT and front pipe and it's MOT time.Simmo, thanks for the tip. I'll get that checked but when it started I stuck it on the ramp and it was clearly the ceramic inards that had broken away from the shell. There was also quite a big drop in performance for the first couple weeks.